Simple test method of capacitance Super capacitor

A simple test method for super capacitance of capacitance topic

If you need to accurately test the parameters of the supercapacitor, need to set up a test platform, to have a data acquisition system, to have data processing capacity, if nothing, but also need to test, in fact, there are methods, but the means are relatively humble, this is the title of "simple" existence of meaning.

So, the headline is a little gallimaufry, and the word is actually:

The test method involves three parameters of the supercapacitor: capacitance, ESR and leakage current.

L Capacitance and ESR test

Fig 1:measuresetup for C & ESR

Fig 2:picture ofsuper Capacitor measurement Setup

What you need.

Handsome people can see, the front said nothing can also be measured, really just a joke, if you really is nothing, then,

1. Digital storage oscilloscope (at least 2 channels, 20MHz bandwidth limit, pulse trigger);

2.2 oscilloscope probes;

3. DC power supply;

4. High power resistance;

5. Manual switch;

6.0.1uF capacitance;

7. Tested supercapacitors.

Capacitance measurement principle

The RC time constant is measured, and the R value is known as the C value.

Steps

1. Keep the company in accordance with FIG1;

2. Charge the super capacitor;

3. Press the switch, let the capacitance discharge, with the oscilloscope to measure the power-off curve at both ends of the capacitor;

4. Theoretically, after a time constant (), the voltage should be reduced to 36.8% of the initial voltage. Read the time from the oscilloscope and divide by the value of the series resistor.

Like what:

Fig 3:discharge for capacitance measurement

Principles of ESR Testing

Since the change is not big, so we can begin to discharge the capacitor in a very short time (such as 50US) capacitor as a constant voltage source, due to the existence of ESR, the capacitance will have a sudden voltage drop, with this drop voltage divided by the current is the value of ESR. So what is the current measurement, using an oscilloscope to measure the voltage at both ends of the series resistor (2.2 Ohm in Fig 1), then dividing by the resistance value is the current.

For example, the purple black line is the super capacitor began to discharge the voltage curve, the pink line is the voltage at both ends of the series resistor.

Fig 4:waveforms for ESR measurement

L Leakage Current Test

Fig 5:measurement setup for leakage current

Fig 6:picture of Super capacitor leakage measurement Setup

This principle is very simple, to the capacitor charge good power, and then use a multimeter to test the voltage on both ends of the resistor, measured him for dozens of hours, OK.

The following is the General Electric leakage curve of super capacitor, can refer to:

Fig 7:trend of leakage current

Resources

"Application Note AN1005 revision 2.1Simple measurement of supercapacitor Parameters"

Capacitor Super Capacitor simple test method